static void Main(string[] args)
{
var lines = File.ReadAllLines("input.txt");
var reactions = lines.Select(Reaction.Parse);
var factory = new NanoFactory(reactions);
var res1 = factory.GetOreRequirementFor(new ReactionItem(Chemical.FUEL, 1));
Console.WriteLine($"Part I: {res1}");
const long trillion = 1_000_000_000_000;
long min = trillion / res1;
long max = trillion;
while (min < max - 1)
{
long med = (min + max) / 2;
var ore = factory.GetOreRequirementFor(new ReactionItem(Chemical.FUEL, med));
if (ore > trillion)
{
max = med;
}
else
{
min = med;
}
}
Console.WriteLine($"Part II: {min}");
}
public void Part1_Sample1()
{
var reactions = new Reaction[]
{
Reaction.Parse("10 ORE => 10 A"),
Reaction.Parse("1 ORE => 1 B"),
Reaction.Parse("7 A, 1 B => 1 C"),
Reaction.Parse("7 A, 1 C => 1 D"),
Reaction.Parse("7 A, 1 D => 1 E"),
Reaction.Parse("7 A, 1 E => 1 FUEL")
};
var factory = new NanoFactory(reactions);
var res = factory.GetOreRequirementFor(new ReactionItem(Chemical.FUEL, 1));
Assert.Equal(31, res);
}
public void Part1_Sample2()
{
var reactions = new Reaction[]
{
Reaction.Parse("9 ORE => 2 A"),
Reaction.Parse("8 ORE => 3 B"),
Reaction.Parse("7 ORE => 5 C"),
Reaction.Parse("3 A, 4 B => 1 AB"),
Reaction.Parse("5 B, 7 C => 1 BC"),
Reaction.Parse("4 C, 1 A => 1 CA"),
Reaction.Parse("2 AB, 3 BC, 4 CA => 1 FUEL")
};
var factory = new NanoFactory(reactions);
var res = factory.GetOreRequirementFor(new ReactionItem(Chemical.FUEL, 1));
Assert.Equal(165, res);
}